Cuttings;Now You Don't See It, Now You Do: Asparagus

By Cass Peterson

Published: February 25, 1996

There is something almost mystical about asparagus. One warm spring day you tramp through the garden, checking out the little lettuce seedlings and other early crops, and the asparagus bed is just a patch of barren earth. The next day you wander through again and there's the asparagus, six to eight inches tall, fat, succulent and ready to eat.

This is faster action than you get from anything else in the garden, except possibly bindweed.

Asparagus is usually thought of as a crop for the patient gardener because it takes a couple of years to establish itself before it can be harvested. After that, it is a perfect crop for the impatient gardener. It just pops out of the earth, sweet and tender and instantly available for dinner.

Its disadvantage, other than the time lag between planting and first harvest, is that it takes space. The rule of thumb is that a patch large enough to satisfy an average family of asparagus lovers should contain at least 50 plants, set 18 inches apart. That translates into a planting bed at least 75 feet long and 3 feet wide.

On the other hand, an asparagus bed can do double duty as an ornamental "hedge." Once the harvest is done for the year, the remaining spears are left to grow into tall, ferny foliage -- perfect for camouflaging fences or providing a feathery backdrop for the rest of the garden.

Asparagus is a member of the lily family, native to the seacoasts of Europe, Africa and Asia. It is a hardy perennial and can be grown in any place that has a dormant season. For most of us, the dormant season is winter, when the ground is frozen, but asparagus will also go dormant in dry seasons, so it can be grown in warm desert climates as well. Gardeners in climates that are mild and wet, like Florida and the Gulf Coast, will have trouble growing asparagus.

Planted in decent soil, in full sun and fertilized regularly, an asparagus patch will produce for 20 years or more. So it pays to get it off to a good start.

Back in the 16th century, when gardeners apparently believed anything, herbalists counseled that asparagus would spring up if one planted the crushed horn of a wild ram. I cannot vouch for this method, but I suspect it's a lot easier to plant asparagus crowns.

"Crown" is the term for an asparagus root, an octopuslike tangle of fleshy white rhizomes. These can be bought by mail or at garden centers in early spring. Two-year-old crowns are larger, but year-old crowns are easier to plant and will produce asparagus just as quickly.

The first rule in planting asparagus is to be sure the soil is as free of perennial weeds and grass as possible. Once established, asparagus does a reasonably good job of shading out pesky weeds, but young beds are easily overrun by dandelions and such and are difficult to hoe.

I ignored this rule when planting my first asparagus bed, and I pay for it annually. The bed is still producing well after 10 years, but the famous wild-foods forager Euell Gibbons probably had an easier time stalking wild asparagus than I do foraging through the burdock and thistles in my domesticated patch.

The bed should also be well supplied with well-rotted manure, compost, leaf mold or any other organic amendment you have on hand. A generous sprinkling of ground limestone -- enough so that it looks like light snow before you mix it in -- will supply the calcium the asparagus needs.

The time-honored method of planting asparagus calls for digging an 18-inch-deep trench, laying in the asparagus crowns and then covering with about three inches of soil. As the plants grow, you pull in more soil to cover the stems until the trench is completely filled.

The reason for the deep trench is that asparagus roots tend to rise to the surface of the soil over time, and crowns that grow too shallowly produce fewer spears.

Deep planting was thought to keep the bed productive longer. But deep planting also delays the harvest each spring because it takes a while for the soil to warm to the depth needed to awaken the asparagus buds.

Nowadays, most gardeners plant new asparagus crowns in a trench just three or four inches deep. To counteract the roots' tendency to rise, add a few inches of new soil (or compost or leaf mold or whatever) to the top of the bed every other spring. This addition keeps the asparagus growing at the right depth, takes care of its fertility needs and helps smother out weeds.

When planting, untangle the roots as best you can, and spread them out flat in the trench, like a large white spider, with the center of the crown facing upward. Ideally you should space the crowns 18 inches from center to center, but if your soil is rich enough you can place them 12 inches apart. Fill up the trench, and water thoroughly.

In a few weeks, the asparagus will start sending up spindly spears. Do not cut any of them. They will quickly sprout out into asparagus's characteristic ferny foliage. Your only job the first year is to keep the bed reasonably weed-free.

Some gardeners mulch asparagus beds, but to be effective against weeds the mulch must be fairly thick. If it is thick enough to foil weeds, it will also restrain the emerging spears, so they come out looking more like shepherd's crooks than asparagus.

The second spring, the spears will be considerably fatter. Although there are varieties (among them the hybrid Jersey Giant) that are said to be harvestable the second year, you will be wise to harvest sparingly, if at all. Any spear you harvest will not develop into foliage, and it is the foliage that feeds the roots, strengthening them so that they will produce many spears the next year.

By Year Three, you can indulge yourself in garden-fresh asparagus for a couple of weeks. By the fifth year you should be able to harvest asparagus for 6 to 8 weeks before you must stop and let the remaining spears turn into foliage.

Harvesting asparagus is literally a snap. Commercial growers usually cut the spear with a sharp knife a little below ground. This assures maximum weight, but the lower part of the spear is often fibrous and has to be peeled before cooking. I prefer just to grab the spear and bend it sideways until it snaps. That way every part of the spear is tender, and I never have to peel asparagus.

Asparagus has few insect enemies other than the asparagus beetle, which lays its tiny black eggs on the emerging spears in early spring. Mature plantings are seldom troubled by asparagus beetles, because those early-spring spears are usually harvested and eaten before the beetle can lay its eggs on them.

Rust and fusarium root rot are more common problems. You can avoid these by planting in a well-drained site and planting resistant varieties like the ever popular Mary Washington or a newer all-male hybrid.

Asparagus plants are either male or female (you can tell the female ones by the little red seed pods hanging from the foliage in the fall). Male plants are said to be more productive because they do not waste energy on seed production. I haven't found much difference in yield, and in any case I like the decorative effect of the seed pods.

White asparagus, popular in Europe, is not a separate variety. It is ordinary asparagus, grown under high mounds of earth to keep the sun from reaching the spears and turning them green. You can grow it, but remember that it is pricey because it is extremely labor-intensive.

Frost-blackened asparagus ferns can be cut down immediately or left to provide a light mulch over winter. But be sure to remove them fairly early in the spring. You wouldn't want to miss spotting that first mystical spear.